Please use the VirusTotal free service if you receive unsolicited / spam emails containing file attachments.

Never open such attachments but instead save the file to your desktop (or where you prefer and will remember later), then go to the VirusTotal web site then use the options shown to upload the file to be checked by a comprehensive range of different antivirus tools.  This will provide a report showing what risk is involved if you open the file on your computer.

Don't open attachments from email addresses that you may think you recognise without confirming that that person did actually send you the file and can tell you why and what it contains etc.

To check the actual email address of the sender of email attachments, use the option (if available) in your email program to look at the email headers or source information.  E.G. Mozilla Thunderbird provides the option in the View menu to show the Message Source (Ctrl+U).  Look for slight variations on the expected address that might suggest that the sender isn't the person you initially might have thought it to be! 

For more information see the following PDF document:
How to identify a SPAM / potential Malware email